Results from the spin programme at COSY-ANKE

TL;DR

This paper summarizes key results from the COSY-ANKE spin programme, including precise eta-meson mass measurement, spin-dependent neutron-proton scattering analysis, and pion production cross sections at 353 MeV.

Contribution

It reports novel high-precision measurements and detailed spin-dependent analyses that advance understanding of meson properties and nucleon interactions.

Findings

Eta-meson mass determined with high precision

Detailed spin dependence of neutron-proton elastic scattering

Successful partial wave decomposition of pion production data

Abstract

Some of the important results from the COSY-Juelich spin programme are summarised. These include the measurement of the deuteron beam momentum through the excitation of a depolarising resonance, which allowed the mass of the eta-meson to be determined to high precision. The charge exchange of polarised deuterons on hydrogen gave rise to a detailed study of the spin dependence of large angle neutron-proton elastic scattering amplitudes. The measurements of the cross section and analysing powers for pion production in both pp and pn collisions at 353 MeV could be described very successfully in terms of a partial wave decomposition.